Lateral magnet assemblies

ABSTRACT

A lateral magnetic assembly adapted to be mounted on the neck of a color cathode-ray tube to adjust color electron beams is comprised by a first magnetic member having three equally spacedapart radial projections, a second magnetic member having two radial projections each interposed between adjacent radial projections of the first magnetic members, inner ends of all radial projections terminating on a circle, a permanent magnet and clamping members formed on the first and second magnetic members to rotatably support the permanent magnet.

United States. Patent [72] Inventor Takeyoshi Sohma Funabashi, Japan[2]] Appl. No 41,470 [22] Filed ,May 28, 1970 [45] Patented Sept. 28,1971 Denki Onkyo Company, Limited Nishirokuzo, Ohota-ku, Tokyo, Japan[73] Assignee [54] LATERAL MAGNET ASSEMBLIES 3 Claims, 3 Drawing Figs.[52] US. Cl 335/212, t 313/77 [51] lnt.Cl H01! 1/00 [50] Field of Search335/212; 313/76; 1/77 [56] References Cited UNITED STATES PATENTS2,813,212 ll/l957 Grundmann FOREIGN PATENTS 208,818 3/1956 AustraliaPrimary ExaminerJ. V. Truhe Attorney-Chittick, Pfund, Birch, Samuels &Gauthier ABSTRACT: A lateral magnetic assembly adapted to be mounted onthe neck of a color cathode-ray tube to adjust color electron beams iscomprised by a first magnetic member having three equally spaced-apartradial projections, a second magnetic member having two radialprojections each interposed between adjacent radial projections of thefirst magnetic members, inner ends of all radial projections terminatingon a circle, a permanent magnet and clamping members formed on the firstand second magnetic members to rotatably support the permanent magnet.

PATENTED SEP28 I9?! FIG. 2

FIG.

FIG. 3

TAKEYOSHI SOHMA INVENTOR BY W H MQM BACKGROUND OF THE INVENTION Thisinvention relates to improvements of a lateral magnet assembly adaptedto be mounted on a three-beam-type color cathode ray tube.

As is well known in the art in the three-beam-type color cathode-raytube, one of three electron beams, particularly a blue beam is requiredto be adjusted in the lateral direction (horizontal direction) withrespect to red and green beams. The lateral magnet assembly is utilizedto attain this object. Among various types of lateral magnet assemblies,a lateral magnet assembly utilizing six-pole magnets was found mostsuitable. The lateral magnet assembly utilizing six-pole magnetscomprises two magnets each having alternate N and S poles at positionscorresponding to apices of a regular hexagon, said magnets being made ofannular magnetic members rotatably mounted like a centering magnetassembly. When such a lateral magnet assembly including six-pole magnetsis used the red beam and green beam can be shifted a little in oppositedirections by the lateral movement of the blue beam. This is extremelyadvantageousfor the adjustment of color television tubes.

However, since the six-pole magnet is difficult to magnetize with equalintensity accurate areas of the ring shaped mag netic member, or toprovide accurate symmetrical magnetization it is difficult tomanufacture it. For this reason, the lateral magnet assembly isextremely expensive. Further, in order to attain the desired object overa long period it is necessary to mount the center of the six-polemagnets of the lateral magnet assembly at a position somewhat displacedfrom the center of the neck of the cathode-ray tube so that assemblingof the lateral magnet assembly is troublesome. Further in order to shiftblue, red and green beams only in the lateral direction it is necessaryto rotate two six-pole magnets by means of gears and the like thuscomplicating the construction.

SUMMARY OF THE INVENTION It is therefore an object of this invention toprovide an improved lateral magnet assembly which is simple inconstruction and can be readily mounted on the neck of a colorcathode-ray tube.

Another object of this invention is to provide a novel lateral magnetassembly for color cathode-ray tube capable of moving a blue electronbeam in one lateral direction and green and red electron beams in theopposite direction by a single operation.

Briefly stated, in accordance with this invention there is provided alateral magnet assembly for use in a color cathoderay tube, comprising afirst magnetic member having three equally spaced apart radialprojections acting as magnetic poles, the inner ends thereof terminatingon a circle, a second magnetic member having two radial projections,each inter posed between adjacent radial projections of the firstmagnetic member, the inner ends of the projections of the secondmagnetic member also terminating on a circle, a permanent magnet havingdiametrically opposite N and S poles, and magnetic clamping membersformed on the first and second magnetic members to rotatably support themagnet.

BRIEF DESCRIPTION OF THE DRAWING The invention can be more fullyunderstood from the following description when taken in conjunction withthe accompanying drawing in which:

FIG. 1 shows a front elevation of a lateral magnet assembly embodyingthis invention and mounted on the neck of a color cathode-ray tube;

FIG. 2 shows a side elevation of the lateral magnet assembly shown inFIG. I and FIG. 3 is a diagram to explain the operation of the novelassembly.

2 DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 1 and 2showing the manner of mounting the novel lateral magnet assembly on theneck 10 of a color cathode-ray tube, blue, red and green electron beamsare designated by reference letters B, R and G respectively. The lateralmagnet assembly comprises a first magnetic member 11 of an annulus withone portion cut away and with three radial projections 11a, llb and at asubstantially middle portion and at opposite ends. As shown in FIG. 2,the inner end of each projection is bent at right angles to extend inthe axial direction of the cathode-ray tube. Bent portions of theprojections 11a, llb and 11c are arranged on a circle having a center onthe axis of the cathode-ray tube. The lateral magnetic member furthercomprises a second magnetic semicircular member 12 with radialprojections at the opposite ends. The inner ends of these projectionsare also bent at right angles to extend in the axial direction of thecathoderay tube. These bent portions are also on a circle having acenter on the axis of the cathode-ray tube. As best shown in FIG. 2first and second magnetic members 11 and 12 are disposed in parallel andspaced apart a predetermined distance along the axis of the tube so thatbent portions of projections 11a, llb, 11c and 12a, 12b of magneticmembers 11 and 12 extend in the opposite direction, that projection 12aof the second magnetic member 12 is positioned between projections 11aand 11c of the first magnetic member 11 and that projection 12b of thesecond magnetic member 12 is positioned between projections 11b and 110of the first magnetic member 11. At substantially the middle portions ofmagnetic members 11 and 12 are integrally formed clamping members 11Aand 12A to rotatably support therebetween a cylindrical magnet 13 withdiametrically opposite N and S poles. Clamping members 11A and 12A haveintegral fingers 14 to firmly hold magnet 13.

Although not shown in the drawing these first and second magneticmembers are held in position by a suitable shoulder so as to be readilymounted on the neck of a cathode-ray tube.

When magnet 13 clamped between clamping members 11A and 12A is rotatedto the position shown in FIG. 2 wherein N pole faces clamping member 12Aand S pole clamping member 11A, projections 11a, llb and 110 of thefirst magnetic member 11 will act as S poles whereas projections 12a and12b of the second magnetic member 12 as N poles. The field intensitiesof respective N and S poles are substantially the same. Asdiagrammatically shown in FIG. 3 the magnetic flux of respective polesacts upon blue, red and green electron beams B, R and G. Moreparticularly blue electron beam B is acted upon by the flux betweenprojection llc of the first magnetic member 11 and projections 12a and12b of the second magnetic member 12, red electron beam R by the fluxbetween projection 12b of the second magnetic member 12 and projection11b of the first magnetic member 11, and green electron beam G by theflux between projection 12a of the second magnetic member 12 andprojection 11a of the first magnetic member 11. Assuming that electronbeams B, R and G travel from the rear side to the front side of thesheet of drawing then blue electron beam Bwill be subjected to a forceacting to the left as viewed in FIG. 3 whereas red and green electronbeams to substantially the equal force acting to the right. As can beclearly noted from FIG. 3, since the force acting upon blue electronbeam B is larger than that acting upon red and green electron beams Rand G, blue electron beam B is moved horizontally over larger distance.This action of the magnetic flux is substantially equal to that of aconventional lateral magnet assembly utilizing sixpole magnets.Consequently, when blue electron beam B is moved laterally, red andgreen electron beams R and G are moved in the opposite direction overthe same small distance, as required.

In this manner, since in accordance with this invention, magnet 13functions to magnetize respective projections Ila, 11b, 11c and 12b ofthe first and second magnetic members 11 and 12, respective projectionswill have the same field intensity. Moreover, rotation of magnet 13results in uniform change in the field intensity of respectiveprojections or magnetic poles and even upon reversal of the polaritiesthereof similar change of the field intensities can be obtained. Inother words, it is possible to reverse the direction of the force actingupon respective electron beams. Thus, adjustment of color beams can beeffected very easily. Moreover, irrespective of which one of twomagnetic members is positioned closer to the face plate of thecathode-ray tube, the effects upon the beams are the same. Since it isnot always necessary to coincide the axis of the cathode-ray tube withcenters of respective projections 11a, 1 lb, llc and 12a, 12b of thefirst and second magnetic members 11 and 12 it is very easy to constructand mount the assembly. Although parallel arrangement of the first andsecond magnetic members 11 and 12 creates some amount of leakage flux,as the direction of the leakage flux is in parallel with the directionof travel of electron beams (in some case in the opposite direction),such leakage flux does not affect the electron beams.

While this invention has been shown and described in terms of apreferred embodiment it will be clear that the configurations ofmagnetic members, of the projections thereof acting as magnetic polesand of the clamping members are not limited to those illustrated.Projections may be disposed in such positions that to produce magneticforce to move laterally the blue electron beam and to move the red andgreen electron beams in the opposite direction over a small distance.

What is claimed is:

l. A lateral magnet assembly comprising a first magnetic member havingthree equally spaced-apart radial projections acting as magnetic poles,the inner ends of said projections terminating on a circle, a secondmagnetic member having two radial projections, each interposed betweenadjacent radial projections of said first magnetic member, the innerends of the radial projections of said second magnetic member alsoterminating on a circle, a magnet having diametrically opposite N AND Spoles, and magnetic clamping members formed on said first and secondmagnetic members to rotatably support said magnet.

2. The lateral magnet assembly according to claim 1 wherein said firstand second magnetic members are disposed in parallel and are spacedapart along the axis of a cathode-ray tube on which said assembly is tobe mounted.

3. The lateral magnet assembly according to claim 1 wherein the innerends of said radial projections of said first and second magneticmembers are bent substantially at right angles to extend in thedirection of the axis of a cathode-ray tube on which said assembly is tobe mounted.

1. A lateral magnet assembly comprising a first magnetic member havingthree equally spaced-apart radial projections acting as magnetic poles,the inner ends of said projections terminating on a circle, a secondmagnetic member having two radial projections, each interposed betweenadjacent radial projections of said first magnetic member, the innerends of the radial projections of said second magnetic member alsoterminating on a circle, a magnet having diametrically opposite N and Spoles, and magnetic clamping members formed on said first and secondmagnetic members to rotatably support said magnet.
 2. The lateral magnetassembly according to claim 1 wherein said first and second magneticmembers are disposed in parallel and are spaced apart along the axis ofa cathode-ray tube on which said assembly is to be mounted.
 3. Thelateral magnet assembly according to claim 1 wherein the inner ends ofsaid radial projections of said first and second magnetic members arebent substantially at right angles to extend in the direction of theaxis of a cathode-ray tube on which said assembly is to be mounted.